Field of the Invention
The present invention relates to a method and an applicator for the perioperative disinfection of medical instruments to be inserted through non-natural openings.
Background of the Invention
The current state of knowledge is as follows.
A large percentage of the group of sepsis infections caused by medical instruments represent diseases and fatalities caused by catheter sepsis, and they are included in the group of theoretically preventable hospital infections within the scope of the treatment of other severe diseases of patients. In Germany alone, it is assumed that they result in several thousand fatalities, leading to costs in the billions.
In light of the scope and the consequences of catheter sepsis there is an urgent need to develop improved methods and means to reduce infections and fatalities associated with catheter sepsis.
The problem of catheter sepsis is essentially caused by the fact that only the surface of the skin is disinfected when catheters are placed, and no methods or preparations are known to also disinfect the insertion channel, where most germs originate, which then contaminate the catheter. Here, deeper skin layers with hair follicles, sebaceous glands and sweat glands also contain germs not reached by surface disinfectants. In particular the problem of entraining germs from deeper skin layers has previously not been solved.
The present invention provides methods and means for the first time which prevent the transfer of fertile germs from the insertion channel to medical instruments and this way fight catheter sepsis.
The application of antiseptically acting chlorhexidine-coatings is already known for catheters. The catheters are already provided with a final coating during their production. The coating is very costly, with a surcharge of USD 30-40 compared to uncoated catheters, thus it is available for a minority of catheters only. At the moment of penetrating the skin the catheter is dry; however in the dry state the coating is ineffective. Accordingly, in spite of such coating, biofilms carrying germs can develop on the catheter.
The product Instillagel is known: a viscous gel for the application in catheterizations of the urinary tract. It is used to provide local anesthesia (lidocaine) and lubrication, and it includes chlorhexidine in an ineffective dosage (0.05%) in a cellulose gel base. It is neither intended nor licensed for the application in vascular catheters. Further, the product Tegaderm CHG is known, which represents a bandage to cover the insertion site of a placed catheter. The product includes a solid gel plate, from which chlorhexidine (2%) is released over an extended period of time in order to prevent an infection at the skin site, from which the catheter projects. It is therefore neither capable of nor intended for preventing any contamination of the catheter during the catheter placement, which may lead to blood sepsis. Additionally, it is only used after the placement of a catheter has already occurred.
The document U.S. Pat. No. 5,015,228 discloses a gel bandage which sterilizes the skin surface at the insertion site as well as the syringe prior to taking fluids (blood) from human vessels or prior to supplying liquids (drugs). This gel bandage also includes a solid gel plate containing disinfectants. However, the substances provided for disinfection in U.S. Pat. No. 5,015,228 are suitable only under certain conditions, because either they require too much time for developing their disinfecting effects and/or they should not enter the body (lack of tolerance). This gel bandage is disadvantageous in that it additionally would aggravate the discovery of veins, because it represents an additional solid layer on the skin, although thin and transparent, which compromises the feeling and visual detection of the vein to be punctured. Furthermore, when penetrating the gel the needle might potentially become clogged by the gel punched out.
The document DE 198 30 421A1 describes a device for treating and caring for the edge sections of artificial body openings and/or the area between the skin of the patient and medical instruments inserted therein (e.g., catheters, fastening screws, tubes) as potential access sites for germs. The device is provided for the use after the placement of a medical instrument.
The disclosure includes a plastic disk to be adhered on the skin as a boundary of the access site (wound) against contaminating influences from the atmosphere, as well as an opening for e.g., an antiseptic gel or a paste, which keeps the skin moist near the access site and may include antiseptic agents which have a disinfecting effect upon the wound. The device disclosed in DE 198 30 421 serves for protection after a surgical procedure in order to support wound healing and to prevent subsequent contamination of the access site from the outside (by external influences).
WO2000033895 discloses cysteine derivatives, such as N-acetyl cysteine, in context with antibiotics for the therapy of biofilms in catheters.
In the U.S.A., (on an annual basis) in 15 million treatment days using central venous catheters (also: central venous catheter (CVC) days) in intensive care units, 80,000 infections in the blood stream caused by catheters (catheter-related blood stream infections (CRBSI)) occur in intensive care units, thus approximately 5.3 infections per 1000 CVC days. This is equivalent to estimated approximately 250,000 infections of the blood stream (also called blood stream infections (BSI)) from all the hospital wards incl. intensive care units (see Guidelines for the Prevention of
Intravascular Catheter-related Infections, CID 2011:52; O'Grady et al.). This causes USD 20,000 (Warren, 2006)-33,000 (Mermel, 2000) additional costs per infection, which adds to USD 5-8 billion of total annual costs. The human loss is paid in 24,300 fatalities per year (2006) (Wenzel R. and Edmond M. N Engl J Med 2006; 355: 2781-2783). In Germany, in 4.7 million CVC-days in inventive care units, 12,000 infections of the blood stream caused by catheters occur (also: catheter-related blood stream infections (CRBSI)), with an increasing trend between the years 2000 and 2008 (1.8; 2; 2.5 and/or 2.6/1000 CVC-days (KISS, Petra Gastmeier)). However, it must be assumed that these numbers are incomplete, because the majority of reports occur on a voluntary basis (personal opinion of Dr. Geffers, KISS). Catheter sepsis causes 6,000-10,000 fatalities per year in Germany.
In the group of endoscopic surgeries, arthroscopies alone are suspected to carry a probability of infection from 0.2 to 0.4%. Here, staphylococci of the skin flora are the primary causes.
The germs occurring most frequently in catheter sepsis include germs of the normal skin flora, such as coagulant negative staphylococci (most common germ in central venous catheter sepsis) as well as enterococcus spp., proteus spp., P. aerugionsa, klebsiella spp., S. aureus, including MRSA, enterobacter spp. and E-coli. 
Only the surface of the skin can be disinfected. However, deeper layers, particularly hair follicles with sebaceous glands or sweat glands, also include germs which can only be reached by disinfectants to an insufficient extent and thus can transfer to the catheter upon placement thereof. Essentially for this reason, for example approximately 10% of all blood cultures are false negatives.
In the context with foreign objects, such as catheters, the transfer of just a few germs is very dangerous. Elek and Conen2 demonstrated in 1957 that merely 100 staphylococci (pyogenes) associated at a foreign object (here: suture material) trigger severe infections in the skin of healthy persons. Contrary thereto, more than 1 million germs were tolerated without any foreign objects. This shows that a very small germ count can lead to severe infections in context with foreign objects.
Furthermore, operating rooms are not sterile, but only show low germ counts. Accordingly, airborne infections and smear infections occur, which can contaminate a catheter.
Today, catheterizations are generally performed in the operating room. Essentially, the puncture site is disinfected. It is performed primarily with alcohol-based disinfectants, in rarer cases with a water-based PVP-iodine. With this method approximately 99% of the germs on the surface of the skin are deactivated3.
The alcohol-based disinfectants may include other disinfecting compounds in addition to alcohol, such as chlorhexidine digluconate (in the following called “chlorhexidine”) or octenidine hydrochloride (in the following called “octenidine”).
In light of the scope and the consequences of catheter sepsis, it is urgently necessary to develop improved methods and means to reduce infections and fatalities associated with catheter sepsis. In particular, no solution has been found up to now in prior art for the problem of transferring germs from deeper skin layers. Additionally, so far there is no solution for the problem that catheters, after removal from the packaging, can be contaminated with bacteria and are then administered in this state.